Radiofrequency transformer



Feb. 14, 1928.

' 1,658,970 H. c. COLBURN RADIO FREQUENCY TRANSFORMER Filed Jan 1926 IN VEIVTOR HERBERT a. co u/P/v MY M I TTORNEYS for the purpose coupling stages or an electron relay system.

he tuned by system tor corn ling together the Patented Feb. 14, 1928.

BADIO"REQUE1'CY TRANSEGRIYIER.

Application filed January iis invention relates generrlly to a rz.- dio frequency transformer especially adapted w ether me it is an object this invention ency a variable condenser, used with on amplifying different electron relay stages, will nose the systen'l to faithfully repent signal energy Without distortion or without causing local oscillotions.

it is r. further object or this i1 "*ention to devise a radio frequency transformer in which high frequency losses will be reduced 1 mirinum.

'nvention possesses other adv-enteoine of which with the foreforth at .tion where l mil outline in l here se ected for drawing zcc vmpzrnying n. forms oi in inrcn stood that I do not to. since the invention as expressed in the whims may be GllllEOtllQ-ll in a plurality of drawings:

elevation ot :1 iy invention. 2 .1 side View or Fig. l.

l) is un elevation of 3. term for transsfinding; a preferred type of trensforr e" cinbo ing my invention, only it fraction or the Winding being shown thereon.

Figure l a side view of the torm shown Fighre 5 is a diagrammatic development or? the pre'tcrred form ot winding; and

ing the nmou ot the engulsr progressions length in the fol Serial No. 72,235.

of the conductor a pusses along the face or the spiders r1, one s ider to the other, it is po sihic to produce a Winding in which the succcc ve turns are juxtaposed for short dis 1c ion points, and at other points on per 1011 O; the successive turns r nere is thus closely. indmg will rare little the- 1 eci'y; with-elmre due to the Jail 01' Winding spiders ll and 12, the operofion of Winding is rendered simple end uicl".

The manner winding is best described b I the aid or the lilizw'rznn Fip'. In this diagram, ruoiul slots in spider i1 are numb .d consecu ively from 1 to to, and the corros on ciin bored 1 to A Sturtmg at slot 1, the conductor l3 enters slot o, the angular distance between slots i one 3 heing spanned on the side or soider ll.

'lhence conductor enters slot by the conduc 4 in this instance '0 the creed by going from slot 5 the conductor proceed side of spider 12 to slot '2". the angular adrance being the same as before. Thence conluctor l3 crosses back to spider ll. and eners slot 9. From this point on, the Winding procedure repented, and may be described merely by the numbers of the slots in which the conductor passes. Thus the succeeding steps may be designated slot numbers ll-1315-2 l6-8'- etc.

It is to be particularly noted that a complete turn or the conductor ends up between slots 15 and 2. and that the succeeding turn, starting there is engnlurly displaced by one slot with re pect to the first turi Furthermore, toe succeeding turn is adjacent the first turn for comparatively short angular distances, represented by the distance between slots 2 and 3, for example. This result is due to the fact that step-by-step angular advances of the conductor *3 in passing; from one spider to the other are not even divisions of a complete circle, whereby at the end of a turn the conductor is passtraversed il equal once trev r rom slot ing between dit srent slots than at the be by the tall ginning of the turn. This result is secured in'the present instance by having an odd number of slots, and by making thestep-bystep advance of the conductor 13 equal to the space between an even number of slots: in this instance two. The winding arrangement can obviously be varied considerably from that shown; For example, the step-bystep angular advance of the conductor 13 could'be made non-uniform, and the numberof slots in the spiders can be varied as desiredl The important point is however thatsuceessive turns do not occupy similar positions as regards the slots. When that condition is fulfilled, the conductor will gradually build up as successive turns are placed on the spiders to form a criss-cross arrangement between the spiders as shown in Fig. 2. v

As best shown in Fig. 1, my invention comprises three separate and distinct coils S S and P, preferably wound in the manner above indicated, the coils S and S being connected in series and constituting the secondary of the transioriner, and the coil P the primary. It w ll be observed that the primary coil P is positioned between the two secondary coils S and S and that all three coils are radially superimposed upon each other. In the preferred form of any invention, the primarycoil'P is wound in a direction opposite to the secondary coils S -and S If desired, the spiders 11 and 12 may be used only as a temporary support for the coils, and after winding they may be cut out or otherwise removed,'such as is shown in Fig.6.

In Figs. 1 to 4 however, I show a construction designed for permanent utilization of the spiders 11 and 12. For this purpose a tubular spacer 1a of insulating material is fastened between the spiders 11 and 12, as by the aid of a screw 15 and a nut 16. Washers 17 may also be provided external- ,ly of the spiders. This screw is made long enough to serve as a terminal post for one terminal of a conductor Wound on the spider. Other terminals are formed by three other screws 18, 19 and 20 and the nuts21. These screws of course are located radially inside of the smallest diameter turn of the coil.

The coils S and S are connected'in series, and the free end of coil S may be connected to the screw 18 while the free end of coil S may be connected to the screw 15. One

end of the coil P may beconnected to screw 19 while its opposite end may be connected to screw 20, in a manner readily understood.

As illustrated in Fig. 5, the straight portions of the successive turns of conductor overlap each other; for example, as between slots 2 and 3, as well as between slots 6 and 7. ,This successive overlapping is a feature of my winding, as well as the crossing over between the two spiders.

It has been determined by experiment that one of the most important features of this invention is the winding of the primary coil in the opposite direction from the secondary. If the primary is wound in the same direction, a radio receiver incorporating such a transformer for coupling together the electron relays in cascade, will'oscillate locally even though the connections to the primary coil are reversed. However if the primary is wound in the opposite direction. the receiver seems to be stabilized and will not oscillate locally, this condition being independent of the manner in which connections 7 tions joining the latticed portions, and a primary coil wound adjacent one peripheral face of the secondary coil, said primary coil being likewise .latticed and wound in a dicoil.

2. A radio frequency transformer comprisin a bank wound secondary wound in two rection opposite to that of the secondary concentric sections, the loops of the wire being latticed across the width of the coil to form a cellular structure and having circumferential portions joinmg the latticed portions, and a primary coil wound similarly to the secondary coil but in the opposite direction, said primary coil being interposed between the two sections of the secondary coil.

In testimony whereof, I have hereunto set my hand.

HERBERT C. COLBURN. 

